Art of mixing



June 21, 1949. I v EAMAN 2,4733% ART OF MIXING Filed June 24, 1943ATTORNEYS Patented June 21, 1949 UNITED S TATES PATENT QFFICE ART OFMIXING Harry J. Seaman, Milwaukee, Wis.

Application .lune'24, 1943, SeriaIiNO. 4923114 (Cl..9'4i44;)

1 Claim. 1

This invention relates 'to improvements in the art of mixing. It isparticularly concerned with apparatus and methods for pulverizing andmixing materials situ.

It is a primary object of the invention to secure in a single traverseof the work a more complete distribution and intermixing of all gradesand sizes of particles of material than has heretofore been possible.While the invention is not limited to any specific class of materials ortype of mixing operation, it may be exemplified by referring to the useof the invention in making soil-concrete. The use of clean sand,substantially free of clay, used to be thought necessary for themanufacture of strong concrete. has been found that ordinary soil mixedwith cement will give a very strong concrete provided the soil particlesare reduced to sufficient fineness and the "cement is distributedthrough the soil particles sufiiciently thoroughly, and the fines, bothof soil and cement, are distributed between the coarser particles insuch a manner as to leave no voids. When these conditions are satisfied,the resulting concrete is extremely compact and dense and has greatstrength.

Other typical mixing jobs involve the stabilization of soil with sand"asphalt or asphalt emulsion or mixtures of sand with clay, or themixing of binders with materials other than soil. It has heretofore beenproposed to do all of these mixing jobs by traversing the materials tobe mixed with a soil tiller of the general type shown in my formerPatent 2,214,702, granted September 10, 1940. As compared with themixing job done by the apparatus there illustrated, I seek to securegreatly improved thoroughness of mixing and distribution by means of thepresent invention.

t is another object of the present invention to provide for thelevelling of the surface traversed by the apparatus to an improveddegree, leaving a smooth, level, hardsurface irrespective of suchsubstantial irregularities as transverse furrows in the ground overwhich the'process and equipment are operated.

In the drawings:

Fig. 1 is a view partially in side elevation and partially inlongitudinal section showing .apparatus for the practice of thisinvention.

Fig. 2 is a diagrammatic view in section showing the apparatus inoperation for the practice of the method.

Like parts are identified by the same reference characters throughoutthe several views.

In general, the apparatus is quite similar to that In past years, it edisclosed in my former patent identified above. There is a wheeled frame3 from which power is transmitted through the housing -4 to a shaft 5which carries "a number of springtines at '6. This shaft projectslaterally from a gear case '1' to which is connectedasupporting shoe 8,the "shoe being "adjustable through means not here pertinent, eitherclockwise or counterclockwise about the axis of the shaft '5 todetermine the level at which the device will operate. The shoe tends toridesubs'tantia lly horizontally and, according to its angularadjustment, the case .I and shaft '5 will be supported at 'difierentlevels with reference to the *ea-xth'tra'versed.

A part of the weight of the housing 4., case '1 and the rotary mixingassembly 5, 6, is carried by utension spring 9 supporting the housing 4from the post IU of the frame. Another part of the weight of theassembly is supported .by means of link I I andcompression spring f2from a subf-rame 15 which is pivoted at T6 to the frame and adjustableby means of the hydraulic cylinder 1? and piston 18.

The rotary mixing assembly is enclosed by a hood EB-connectedtothe'irameby means of arms El for upward and downward oscillation. Thelink rod fiend compression spring 23 partially support the weight oi thehood from the subframe l5 so that the hood, like therotary mixingassembly, will partake .of the adjustment effected by the hydrauliccylinder and piston I1 and 18. While the general relation of the hood tothe mixing assembly is thus approximately maintained, the "separate linkrod 22 and spring 23 permit the hood to'have bodily movementindependently of the mixing assembly.

For ,purely till'ing purposes, the hood preferably comprises hingedly'yieldable panels '24 and 25 against which the :material dislodged bythe tines 8 is primarily directed for pu'lverization. The *yie'ldabilityof these "panels upon the respective hinges permits them to clear stonesand other obstructions such as are "encountered when the machine isbeing used for tillage. It is,

' however, an important feature of the present invention that thesepanels be latched down tojpreclude their movement independently .of thehood in its -'ent'irejty. For thisjpurpose, "the panel .25 is providedwith an 1933! "at {26 through which bolt 2-? passes into engagement withthe 'keeper'28 on the side of the hood. This precludes anyindependent'y'ielding movement of the panels when the apparatusis beingused for mixing.

*Theuseo'f a demountslble iforarninous plate to, serving as a screen, isoptional. The plate is pro- 3 vided with a hook at 3! which may beengaged over a cross rod 32 of the hood. Where the plate is used, ittends to force toward the bottom of the excavation made by the tines Bsuch irreduceable coarse particles as will not penetrate the aperturesof the plate.

While apparatus other than that illustrated may be used to perform themixing method embodying this invention, the apparatus disclosed isparticularly adapted for use in the practice of said method. In order touse it for mixing, as distinguished from tillage, the apparatus isoperated with the hood panels 24 and 25 fastened down so that thechamber provided by hood is substantially closed. It is immaterial thatthe slots 33 and 34 for the housing 4 and the link rod l i are open. Theplaces where closure is most desirable are at the front and rear. Thepanel is operated at such a level, as indicated in Fig. 2, as tofunction as a scraper. Being locked aaginst yieiding, it scrapes beforeit a substantial pile of pulverized material at 35. Thus the chamberwithin which the rotary mixing assembly functions is not only closed bythe panel 25 but also is sealed by the mass of pulverized material 35scraped ahead of such panel. This results in a very substantial portionof the pulverized material being caused to circulate around the interiorof the generally cylindrical chamber in which the rotary mixer isoperated. Such material, comprising mostly fines but some coarsematerial, moves clockwise with the mixing assembly, as viewed in thedrawings, and is discharged from the free forward margin 36 of the hoodto fall in a transverse windrow directly in u the path of the tines E ofthe mixing assembly. Thus, as such assembly rotates at high speed, itnot only cuts into the previously unworked material at 3'! but, inreaching such unworked material, the tines pass downwardly through thefines and aggregates which have already passed about the hood and lodgedin the windrow 38. The windrow 38 approximately, although notnecessarily completely, closes the hood 20 at its forward side. As aresult of the passage of the tines through this windrow and then throughthe previously unworked material, a much higher degree of perfect mixingaction is secured than would otherwise be possible.

If the panels 24 and 25, or particularly the latter, are left free forhinged movement, as in ordinary tillage, the amount of material making acircuit about the interior of the hood and deposited in the windrow 33is greatly reduced and the mixing action is correspondingly lesseffective. Another mixing operation is also less effective under thosecircumstances. The pile of material scraped at 35 before the panel 25,when the panel is latched down, is in itself a very important factor insecuring a perfect mix. The particles in the pile 35 are continuallycaused to churn over upon each other as the scraper portion 25 of thehood advances. Finally, such particles are forced into intimate contactby the wedging action and weight imposed thereon as the scraper passesover them. When the scraper panel 25 is not fastened down, even a smallpebble or lump will lift this panel to discharge a very considerablequantity of the material that would otherwise be scraped forwardly. Itis not possible under such circumstances to accumulate any mass ofmaterial at 35 because such mass of material, apart from any stone orlump, would of itself effect the lifting of the panel and the dischargeof the material.

It will be apparent that the device and method as disclosed will alsoeffect a levelling operation. As indicated at 39, the material not yetacted upon by the device is, or may be, quite irregular. The surface at40 of the material compacted and leveled by the scraping panel 25 issmooth and hard. It is even possible to operate transversely of thefurrows of a previously plowed field and to leave such a fieldcompletely level. The scraping panel 25 operates to accumulate theexcess material of the ridges and to deposit such excess material in thefurrows.

As will be apparent from the general description of the invention, ifthe material to be mixed comprises more than one separate ingredient,the several ingredients are aggregated or associated in the path ofadvance of the mixing implement and hood. For example, where cement orasphalt is to be mixed with soil, or sand is to be mixed with a claysoil, the cement, asphalt or sand may be deposited in piles or windrows4| so distributed over the surface of the natural soil as to giveapproximately the correct proportions when mixed. Any number ofingredients may be thus associated, whether or not one or more of thesecomprises natural soil.

By operating the rotary mixing assembly in a substantially closedchamber and ahead of an inclined scraper edge as herein disclosed, Ieffectively distribute the particles of differing sizes throughout themass of material acted upon and effective!" compress and compact thematerial to eliminate voids and secure a perfectly mixed product.Referring again to the soil-cement example chosen to illustrate theinvention, a core taken from concrete made of soil and cement mixed inaccordance with this invention will be smooth, compact and dense ascompared with the relatively coarse, porous and rough concrete producedby apparatus and methods heretofore known.

I claim:

In a device of the character described having a rotary tilling head,means for rotating said head at high speed in a direction to throwtilled material rearwardly and a hood with a rearwardly inclined panel,the combination with said hood and panel, of an inclined foraminousscreen mounted within the hood forwardly of the panel and at a steeperangle of inclination than the panel, said screen having openings adaptedto pass fine material dislodged by said head and to force coarsermaterial downwardly to be covered by such fine material, and means forreleasably securing the panel against change of angular positionrespecting the hood, said panel having a hinged connection with the hoodwhereby to be floating when said means is released.

HARRY J. SEAMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,512,596 Hamshaw Oct. 21, 19241,676,646 Funk July 10, 1928 1,878,442 Hamshaw Sept. 20, 1932 2,090,290Gardner Aug. 1'7, 1937 2,181,320 Flynn Nov. 28, 1939 2,214,702 SeamanSept. 10, 1940 2,289,334 Matter Oct. 20, 1942

